Well, here’s the thing
It may be easier to list the episodes they aren’t in. 😉
They are in the background or mentioned in nearly every episode in seasons 1-3. There may be some I missed because sometimes I get caught up in the story and forget to scream and point when they walk by, but they hang out in the Zocalo a LOT.
(Which begs the question, what do Pak’Ma’Ra shop for?)
I think they are not in Soul Hunter, Mind War, and Survivors.
Season 4:
I thought they couldn’t possibly be in The Face of the Enemy, but I think Ivanova mentions something about everyone looking like a Pak’Ma’Ra ate their cat.
They are not in Intersections in Real Time.
They are not in Endgame, erm, unless you count their ships as a sighting. (?)
This is about the point in the series where I forget to look for them every time. Next time I should tack a checklist to my TV. So, I don’t know how often they appear in Season 5. Yet.
I have not hunted for them in the movies and the less said about their semi-nude appearance in Crusade the better….
I have just converted someone to B5 and (somewhat unfairly) asked for him to look, but he got caught up in the story, too.